Heat exchanger package with split charge air cooler

ABSTRACT

A combined radiator and charge air cooler package comprises a radiator for cooling engine coolant, and a charge air cooler for cooling charge air having upper and lower portions. The upper charge air cooler portion is disposed in overlapping relationship and adjacent to the upper end of the radiator, and the lower charge air cooler portion is disposed in overlapping relationship and adjacent to the lower end of the radiator, on the face side thereof. Ambient air may flow in series through the upper end of the radiator and the upper charge air cooler portion, and through the lower charge air cooler portion and the lower end of the radiator. The charge air cooler portions are operatively connected such that the charge air may flow between the lower manifold of the upper charge air cooler portion and the upper manifold of the lower charge air cooler portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to heat exchanger devices for cooling fluids usedin an engine of a motor vehicle, and more particularly, to a heatexchanger package including a coupled radiator and charge air cooler foran engine of a heavy-duty highway truck or bus.

2. Description of Related Art

Heat exchanger packages comprising a radiator and a charge air cooler,also known as an intercooler, have been used for years in over the roadhighway trucks and buses and other heavy-duty motor vehicles. Theradiators provide cooling for the engine coolant, usually a 50-50solution of water and anti-freeze. The charge air cooler receivescompressed, charge or intake air from the turbo- or super-charger andlowers its temperature before it enters the engine intake manifold,thereby making it denser, improving combustion, raising power output,improving fuel economy and reducing emissions. In order to optimize heattransfer in a given heat exchanger package size, the factors of coolingair flow, heat exchanger core restriction, cooling air flow split andcooling air approach and differential temperature must be balanced.

Numerous configurations of the radiator/charge air cooler heat exchangerpackage have been disclosed in the prior art. Placing both the radiatorand charge air cooler side-by-side, so that the full frontal area ofeach of the cores are exposed to ambient cooling air, provides the bestperformance, but requires the largest package frontal area. Limitationsin the frontal area of radiator and charge-air cooler heat exchangerpackages have been sought in order to accommodate the smaller frontalarea of motor vehicles, as a result of improved vehicle aerodynamics.Heat exchanger packages with smaller frontal areas have been disclosedfor example in U.S. Pat. No. 4,737,727, U.S. Patent ApplicationPublication No. 2003/0106669, and in U.S. patent application Ser. No.10/289,513.

In another prior art radiator and charge air cooler heat exchangerpackage, depicted in FIG. 1, the charge air cooler is split between anupper unit 101 and a lower unit 103, disposed respectively behind and infront of radiator 107 with respect to the direction of air flow 127.Radiator 107 has a conventional downflow-type tube and fin core 117between upper tank 109 a and lower tank 109 b. Radiator 107 receivescoolant 131 from the engine into upper tank 109 a and the cooled enginecoolant exits as 133 from the lower portion of lower tank 109 b, to betransferred back to the engine. Both charge air cooler units 101, 103are cross-flow type charge air coolers wherein the compressed charge airis flowed horizontally through the respective tube and fin cores 111,113. Compressed, heated charge air 121 is first flowed into verticallyoriented tank 105 a of upper charge air cooler 101, through core 111 indirection 129 a, and into vertical tank 105 b. In unit 101, the chargeair is cooled by air 127 as it exits the upper portion of radiator core117. Thereafter, the partially cooled compressed charge air 123 is thentransferred into vertical tank 105 d of lower charge air cooler 103,where it is then flowed in horizontal direction 129 b through core 113and into vertical tank 105 c, and thereafter exits 125 and flows to theengine intake manifold. In unit 103, the charge air is cooled by air 127before it flows through the lower portion of radiator core 117.Notwithstanding its novel design, the heat exchanger package of FIG. 1did not achieve good performance and did not go into normal production,to the inventor's knowledge. It has now been determined that theperformance of heat exchanger package of FIG. 1 suffered in large partdue to excessive charge air pressure drop through the two charge aircooler units.

Thus there has been a long-felt need to achieve high performance incooling both engine coolant and charge air, while observing strictlimitations in frontal area of a radiator/charge air cooler heatexchanger package.

SUMMARY OF THE INVENTION

Bearing in mind the problems and deficiencies of the prior art, it istherefore an object of the present invention to provide a combinationradiator and charge air cooler which achieves high heat transferperformance with a minimal frontal area.

It is another object of the present invention to provide a heatexchanger package for cooling different fluids which minimizes thepressure loss to the fluids.

It is a further object of the present invention to provide a method ofcooling fluids such as engine coolant and charge air used in the engineof a motor vehicle which optimizes heat transfer of those fluids toambient cooling air.

The above and other objects, which will be apparent to those skilled inart, are achieved in the present invention which is directed to a heatexchanger apparatus comprising a first heat exchanger for cooling afirst fluid having opposite front and rear faces through which coolingair flows, opposite first and second ends adjacent the faces, and sidesadjacent the faces between the first and second ends. The heat exchangerapparatus also includes a second heat exchanger for cooling a secondfluid having two portions. Each second heat exchanger portion hasopposite front and rear faces through which cooling air flows, oppositefirst and second ends adjacent the faces, and sides adjacent the facesbetween the first and second ends, and includes manifolds at the firstand second ends and fluid-carrying tubes extending substantiallydirectly therebetween.

One of the second heat exchanger portions is disposed in overlappingrelationship and adjacent to the first end of the first heat exchanger,with the first and second ends of the one of the second heat exchangerportions being oriented in the same direction as the first and secondends of the first heat exchanger. One face at the first end of the firstheat exchanger is disposed adjacent one face of the one of the secondheat exchanger portions, such that the cooling air may flow in seriesthrough the first end of the first heat exchanger and the one of thesecond heat exchanger portions. The other of the second heat exchangerportions is disposed in overlapping relationship and adjacent to thesecond end of the first heat exchanger, with the first and second endsof the other of the second heat exchanger portions being oriented in thesame direction as the first and second ends of the first heat exchanger.The other face at the second end of the first heat exchanger is disposedadjacent one face of the other of the second heat exchanger portions,such that the cooling air may flow in series through the other of thesecond heat exchanger portions and the second end of the first heatexchanger. The second heat exchanger portions are operatively connectedsuch that the second fluid may flow between the second manifold of theone of the second heat exchanger portions and the first manifold of theother of the second heat exchanger portions.

The second heat exchanger portions may be operatively connected suchthat fluid may flow between the second manifold of the one of the secondheat exchanger portions and the first manifold of the other of thesecond heat exchanger portions around at least one side of the firstheat exchanger, preferably around both sides of the first heatexchanger. The manifolds of the second heat exchanger portions mayextend across the ends thereof, and substantially from one side of thefirst heat exchanger to the other side of the first heat exchanger.

Preferably, the dimension between the first and seconds ends of thesecond heat exchanger portions is less than the dimension from one sideof the second heat exchanger portions to the other side of the secondheat exchanger portions, such that the fluid-carrying tubes extendacross the shorter dimension of the faces of the second heat exchangerportions. The first heat exchanger may also include fluid-carryingtubes, with the fluid-carrying tubes of the first heat exchangerextending in the same direction as the fluid-carrying tubes of each ofthe second heat exchanger portions.

The sides of the first heat exchanger may be adjacent each of the sidesof the second heat exchanger portions, and the first end of the firstheat exchanger may be adjacent the first end of the one of the secondheat exchanger portions and the second end of the first heat exchangeris adjacent the second end of the other of the second heat exchangerportions. The second end of the one of the second heat exchangerportions may be adjacent the first end of the other of the second heatexchanger portions.

The manifolds of the second heat exchanger portions may extendhorizontally, such that the second heat exchanger portions arevertically separated, or the manifolds of the second heat exchangerportions may extend vertically, such that the second heat exchangerportions are horizontally separated.

At least one of the sides or ends of the first heat exchanger mayextends outward of a side or end of one of the second heat exchangerportions, wherein the first end of the first heat exchanger extendsoutward of the first end of the one of the second heat exchangerportions. Also, at least one of the sides or ends of one of the secondheat exchanger portions may extend outward of a side or end of the firstheat exchanger.

Preferably, the first heat exchanger is a radiator for cooling enginecoolant and the second heat exchanger is a charge air cooler for coolingcharge air, with each of the radiator and the charge air cooler portionsbeing cooled by ambient air. Alternatively, the first heat exchanger isa charge air cooler for cooling charge air and the second heat exchangeris radiator for cooling engine coolant, with each of the charge aircooler portions and the radiator being cooled by ambient air.

In a preferred embodiment, the present invention is directed to acombined radiator and charge air cooler package comprising: 1) aradiator for cooling engine coolant having opposite front and rear facesthrough which ambient air flows, opposite upper and lower ends adjacentthe faces, and sides adjacent the faces between the first and secondends, and 2) a charge air cooler for cooling charge air having upper andlower portions. Each charge air cooler portion has opposite front andrear faces through which ambient air flows, opposite upper and lowerends adjacent the faces, and sides adjacent the faces between the upperand lower ends, and includes manifolds at the upper and lower ends andcharge air-carrying tubes extending substantially directly therebetween.

The upper charge air cooler portion is disposed in overlappingrelationship and adjacent to the upper end of the radiator with theupper and lower ends of the upper charge air cooler portion beingoriented in the same direction as the upper and lower ends of theradiator. One face at the upper end of the radiator is disposed adjacentone face of the upper charge air cooler portion, such that the ambientair may flow in series through the upper end of the radiator and theupper charge air cooler portion. The lower charge air cooler portion isdisposed in overlapping relationship and adjacent to the lower end ofthe radiator with the upper and lower ends of the lower charge aircooler portion being oriented in the same direction as the upper andlower ends of the radiator. The other face at the lower end of theradiator is disposed adjacent one face of the lower charge air coolerportion, such that the ambient air may flow in series through the lowercharge air cooler portion and the lower end of the radiator. The chargeair cooler portions are operatively connected such that the charge airmay flow between the lower manifold of the upper charge air coolerportion and the upper manifold of the lower charge air cooler portion.

In another aspect, the present invention provides a method for coolingfluids used in an engine of a motor vehicle, comprising providing a heatexchanger assembly as described above, flowing the first fluid throughthe first heat exchanger, and flowing the second fluid through thesubstantially directly extending tubes of the second heat exchangerportions and between the second manifold of the one of the second heatexchanger portions and the first manifold of the other of the secondheat exchanger portions. The method then includes flowing cooling airthrough the heat exchanger assembly such that the cooling air flowsthrough both the first end of the first heat exchanger and the one ofthe second heat exchanger portions, and the cooling air flows throughboth the other of the second heat exchanger portions and the second endof the first heat exchanger, to cool the first fluid in the first heatexchanger and the second fluid in the second heat exchanger portions.

The second fluid may flow in sequence through the second manifold of theother of the second heat exchanger portions, the substantially directlyextending tubes of the other of the second heat exchanger portions, thefirst manifold of the other of the second heat exchanger portions, thesecond manifold of the one of the second heat exchanger portions, thesubstantially directly extending tubes of the one of the second heatexchanger portions, and the first manifold of the one of the second heatexchanger portions. The cooling air flows sequentially first through theone of the second heat exchanger portions and subsequently through thefirst end of the first heat exchanger, and also flows sequentially firstthrough the second end of the first heat exchanger and subsequentlythrough the other of the second heat exchanger portions.

Alternatively, the second fluid flows in sequence through the firstmanifold of the one of the second heat exchanger portions, thesubstantially directly extending tubes of the one of the second heatexchanger portions, the second manifold of the one of the second heatexchanger portions, the first manifold of the other of the second heatexchanger portions, the substantially directly extending tubes of theother of the second heat exchanger portions, and the second manifold ofthe other of the second heat exchanger portions. The cooling air flowssequentially first through the first end of the first heat exchanger andsubsequently through the one of the second heat exchanger portions, andalso flows sequentially first through the other of the second heatexchanger portions and subsequently through the second end of the firstheat exchanger.

Preferably, the first heat exchanger is a radiator and the first fluidis engine coolant, and the second heat exchanger is a charge air coolerand the second fluid is charge air, with each of the radiator and thecharge air cooler portions being cooled by ambient air. Alternatively,the first heat exchanger is a charge air cooler and the first fluid ischarge air, and the second heat exchanger is a radiator and the secondfluid is engine coolant, with each of the charge air cooler portions andthe radiator being cooled by ambient air.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention believed to be novel and the elementscharacteristic of the invention are set forth with particularity in theappended claims. The figures are for illustration purposes only and arenot drawn to scale. The invention itself, however, both as toorganization and method of operation, may best be understood byreference to the detailed description which follows taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a perspective view of a prior art radiator/charge air coolerheat exchanger package.

FIG. 2 is a side elevational view of one embodiment of theradiator/charge air cooler heat exchanger package of the presentinvention.

FIG. 3 is a top plan view of the radiator of the radiator/charge aircooler package of FIG. 2.

FIG. 4 is a front elevational view of the charge air cooler portion ofthe heat exchanger package of FIG. 2, without the radiator, and showingcooling fins over only a portion of the tubes of the core.

FIG. 5 is a perspective view of the radiator/charge air cooler packageof FIG. 2.

FIG. 6 is a front elevational view of the charge air cooler portion ofan alternate heat exchanger package, without the radiator, and showingcooling fins over only a portion of the tubes of the core.

FIG. 7 is a perspective view of the radiator incorporated with thecharge air cooler in the alternate heat exchanger package depicted inFIG. 6.

FIG. 8 is a plan or side elevational view of the radiator/charge aircooler heat exchanger package of the present invention in relation to acooling fan.

FIG. 9 is a perspective view of a portion of the heat exchanger packagesof the present invention showing one embodiment of the connectingmanifold between the two charge air cooler units.

FIG. 10 is a side elevational view, partially cut away, showing thecombined radiator/charge air cooler heat exchanger combination of thepresent invention mounted under the hood of a highway truck.

FIG. 11 shows alternate locations of the combination radiator/charge aircooler heat exchanger package of the present invention mounted in therear of a highway bus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In describing the preferred embodiment of the present invention,reference will be made herein to FIGS. 2-11 of the drawings in whichlike numerals refer to like features of the invention.

A first embodiment of the heat exchanger package of the presentinvention is depicted in FIGS. 2-5. A combined heat exchanger package 20preferably comprises a first heat exchanger 22 for cooling a firstfluid, preferably a radiator for use in cooling liquid engine coolantfrom a motor vehicle or other internal combustion engine, and anotherheat exchanger having at least two units or portions 30, 32 for coolinga second fluid, preferably charge air coolers for cooling compressedcharge air from a turbo or supercharger of an internal combustionengine. Although engine coolant will be used to exemplify the firstfluid, and compressed charge air will be used to exemplify the secondfluid, any other fluids may be substituted. Both heat exchangers arenormally in an upstanding, essentially vertical position, and arepreferably rectangular in shape, and the width and length of thecombined heat exchanger package is consistent with the requirements ofthe truck or bus engine compartments. Radiator 22 of the presentinvention is preferably a down flow type radiator, wherein enginecoolant 40 enters through an upper manifold or tank 24 a extendingsubstantially the entire width of the radiator. The coolant is thendistributed from manifold 24 a into attached core 26 having an otherwiseconventional construction, which generally comprises downwardlyextending tubes 23 connected by cooling fins (not shown), so thatambient cooling air 46 may flow from the front face 28 a of the corethrough and out of the rear face 28 b. After being cooled by the ambientair, the coolant then collects in attached lower manifold or tank 24 balso extending across the width of the radiator, and out through thecoolant outlet 44 for return to the engine.

The charge air cooler (CAC) of the present invention preferablycomprises a split pair of vertically separated units or portions 30, 32.Upper CAC unit 30 is disposed in an overlapping fashion with the upperportion of radiator 22, so that the upper edge and sides of CAC unit 30are coincident with and behind the upper edge and sides of radiator 22,with respect to the direction of cooling air 46. Front face 35 a of CACunit 30 is abutted to or slightly spaced from rear face 28 b of radiator22. CAC unit 30 contains an upper tank or manifold 34 a and a lower tankor manifold 34 b and a core 37 a attached therebetween, each extendingsubstantially the full width of the charge air cooler unit. Lower CACunit 32 is positioned in front of the lower portion of radiator 22, withrespect to air flow direction 46, and the lower end and sides of unit 32are coincident with the lower end and lower sides of radiator 22. Rearface 35 d of CAC unit 30 is abutted to or slightly spaced from radiatorfront face 28 a. CAC unit 32 contains an upper tank or manifold 34 c anda lower tank or manifold 34 d and a core 37 b attached therebetween,each extending substantially the full width of the charge air coolerunit. Both CAC cores 37 a, 37 b are conventional tube and finconstruction. Lower manifold 34 b of CAC unit 30 is operativelyconnected to upper manifold 34 c of CAC unit 32, so that charge air mayflow therebetween.

Although positioned in superficially similar manner to the prior artembodiment of FIG. 1, the charge air cooler units of the presentinvention are quite different in that they are either up or down flowunits, and not cross flow units. Thus, as shown in FIG. 5, the enteringheated compressed charge air 50 flows through manifold 34 a and downward52 to be cooled in core 37 a, made up of otherwise conventional tubesand cooling fins, and collected into a lower manifold 34 b. Thiscompressed charge air 54 is then transferred to the upper manifold 34 cof lower CAC unit 32, where the now partially cooled charge air 56 thenflows downward through core 37 b, into lower manifold 34 d, and out ascooled compressed air 58 to be routed to the engine air intake manifold.

As shown in more detail in FIG. 4, each of the cores 37 a, 37 b for theCAC units 30, 32 comprise spaced, vertically extending tubes 36, betweenwhich are disposed serpentine cooling fins 38, oriented to permit airflow through the unit. Such fins should extend between all of the tubesin the core. These tubes may be two (2) rows deep, as shown in FIG. 2,or any other configuration. Both charge air cooler units 30 and 32 havea horizontal width, measured in the direction of the manifolds, which isgreater than the vertical height of each of the units, measured betweenthe manifolds. Improved heat exchanger package performance, and inparticular, improved performance of the charge air cooler units, hasbeen found by utilizing tubes 36 which are as short as possible and asnumerous as possible, given the configuration of the charge air coolerunit. As shown in this embodiment, charge air cooler units 30 and 32employ tubes 36 which are oriented with the shorter vertical height ofeach of the units so that there are a larger number of shorter tubes, ascontrasted to the smaller number of longer tubes as used in the crossflow CAC unit of FIG. 1.

Heat exchanger cores 26, 37 a, 37 b can be constructed of typicalmaterials, for example aluminum, brass or copper tubes and fins.Manifolds 24 a, 24 b, 34 a, 34 b, 34 c, 34 d may be any conventionalmaterials such as plastic, aluminum, brass or copper.

FIGS. 6 and 7 depict another embodiment 20′ of the present inventionwhich is structurally identical to the previous embodiment, with thedifference being that the radiator and charge air cooling units arerotated 90°, so that the CAC units are horizontally separated. Asbefore, manifolds 24 a, 24 b of radiator 22 may be oriented in the samedirection as manifolds 34 a, 34 b, 34 c, 34 d of CAC units 30 and 32. Inthis embodiment, all of the manifolds of the radiator and charge aircooler units are vertically oriented and horizontally spaced and,consequently, the fluid flow through the now horizontal tubes within thecores of the respective radiator and charge air cooler units is nowhorizontal. However, the performance of the heat exchanger package inthe embodiment of FIGS. 6 and 7 is the same as that in the embodiment ofFIGS. 2-5 since the charge air cooler tubes are as short and as numerousas possible given that the horizontal width of the each charge aircooler unit is less than its vertical height. Alternatively, when thepressure drop of the coolant in the radiator is not critical, theradiator can remain as a downflow unit as in FIGS. 1-5, while CACs 30,32are rotated 90° to the position shown in FIGS. 6 and 7.

FIG. 8 depicts the heat exchanger package 20, 20′ of the previousembodiments in relation to a cooling suction fan having fan blades 62powered by a fan motor 60. The heat exchanger package 20, 20′ is in linewith the area swept by the fan blades to move the outside ambientcooling air 46 through each of the CAC units 30, 32 and radiator 22.Preferably, CAC manifolds 34 b, 34 c are positioned in line with thecenter of the fan blades 62 and fan motor 60, where airflow is low ornearly zero. A fan shroud (not shown) may be positionedcircumferentially around the fan blades and the heat exchanger packagetop and side edges to contain and direct the airflow. In operation,ambient cooling air 46 presented to approximately half of the heatexchanger package 20 or 20′ flows sequentially and in series through thefree front face 28 a of radiator core 26 (shown at the upper end), outthrough the rear face 28 b and, now having been heated to above ambienttemperature, then immediately flows through adjacent front face 35 a ofCAC unit 30. After passing through CAC core 37 a, the cooling air passesout through rear face 35 b. In the other approximately half of heatexchanger package 20 or 20′ (shown at the lower end), ambient air 46flows sequentially and in series through front face 35 c of core 37 b ofCAC unit 32, and out of CAC rear face 35 d and, now having been heatedto above ambient temperature, then immediately through adjacent face 28a of radiator 22. After passing through the lower portion of radiatorcore 26, the ambient cooling air then exits through free rear face 28 bof radiator 22. Notwithstanding the fact that it is heated as it passesthrough the fins of the radiator and CAC units, unless otherwisespecified, the term ambient air includes all of the cooling air as itpasses through heat exchanger package.

The operational flow of fluid to be cooled is such that, as shown inFIG. 5, the initially hot engine coolant 40 is received in the upperportion of radiator 22 and cooled as it passes downward 42 throughradiator core 26, given that ambient air 46 is at a lower temperaturethan the incoming engine coolant 40. Incoming compressed charge air 50is normally at a higher temperature than the incoming engine coolant,and is initially passed through upper charge air cooler unit 30. Thisheated charge air flows through core 37 a and is then cooled by air 46,after that air passes through and is heated by the upper portion ofradiator core 26. The partially cooled compressed charge air 54 thenpasses from lower manifold 34 b to upper manifold 34 c of lower CAC unit32. CAC unit 32 is in front of the lower portion of radiator 22 withrespect to the cooling air flow, and as the charge air 56 passesdownward through core 37 b, it is cooled by the fresh ambient air beforeit passes out through manifold 34 d of CAC unit 32 as cooled compressedair 58, which is then routed to the air intake manifold of the engine.

The flow of ambient cooling air may be reversed for the embodimentsdescribed herein, so that it flows in direction 46′ (FIGS. 5 and 7). Toaccomplish this, a blower fan may be used in place of the suction fan toblow air first through the fan and then through the heat exchangerpackage. Additionally, the flow of fluids to be cooled may be reversedfrom that described above. The cooling performance of the heat exchangerpackage, including the CAC units, has been determined to besubstantially the same when reversing the flow of the ambient coolingair, so that it flows in direction 46′, and/or reversing the flow of thecharge air, so that the charge air enters through manifold 34 d andexits through manifold 34 a.

Although in the preferred embodiment of the present invention, there areno non-overlapping regions between the top, bottom or sides of theradiator and the corresponding top, bottom and sides of the CAC units,the heat exchanger package of the present invention may include suchnon-overlapping regions. For example, as shown in FIG. 8, radiator ends25 a′ or 25 b′ adjacent manifolds 24 a, 24 b, respectively, may extendabove and below the corresponding charge air cooler unit ends 39 a, 39d, adjacent manifolds 34 a, 34 d, respectively. Alternatively, ends 39a′, 39 d′ of the charge air cooler units may extend above and below theupper and lower ends of the radiator 25 a, 25 b. As shown in FIG. 3, itis also possible for there to be non-overlapping regions along the sidesof the heat exchanger package. One or both of radiator sides 27 a′, 27b′ may extend beyond the sides of the heat exchanger units 33 a, 33 b.Alternatively, any of the charge air cooler sides 33 a′, 33 b′ mayextend beyond the sides of radiator sides 27 a, 27 b. If any suchnon-overlapping regions are used, the portions of either of the chargeair cooler units or radiator extending beyond and behind the other willthen receive fresh ambient air. Additional heat exchangers typicallyemployed in motor vehicles may be used in the heat exchanger package ofthe present invention, such as oil and transmission coolers, andsecondary charge air coolers units may also be used, either in front ofor behind upper or lower portions of the package.

A preferred embodiment of the manifold connection between the charge aircooler units is depicted in FIG. 9. CAC unit 30 has on it a lower endmanifold 34 b, and CAC unit 32 has on its upper end manifold 34 c. Asdepicted manifolds 34 b and 34 c are connected around both opposing sideedges of radiator 22 by connecting conduits 31 a, 31 b, which pass thepartially cooled compressed charge air 54 from CAC unit 30 to CAC unit32.

Referring to FIG. 10, a heavy duty highway truck 70 is shown includingengine 72 located in engine compartment 76 at the front portion of thetruck. The vehicle includes a lower frame 74 having the combinedradiator/CAC heat exchanger package 20, 20′ mounted vertically at thefront end of engine compartment 74. The fan is mounted within fan shroud78 positioned behind the heat exchanger package. The radiator and chargeair cooler are operatively connected to engine 72 by hoses 71, 73,respectively, which provide the engine coolant and engine charge air.FIG. 11 depicts the heat exchanger package of the invention 20, 20′mounted at the rear of a bus behind grill 82, or at the side near therear (in phantom lines).

Models of the present invention heat exchanger package as compared tothe prior art of FIG. 1 have shown significant reduction in hot side airflow charge air pressure drop of a turbocharged engine, with aninsignificant increase in charge air and coolant temperatures. Suchincreased performance is shown in such models even at high charge airflow rates.

Thus, the heat exchanger package of the present invention provides acombination radiator and charge air cooler which achieves high heattransfer performance with a minimal frontal area, while minimizingpressure loss to the fluids. It is particularly useful to cooling fluidssuch as engine coolant and charge air used in the engine of a heavy dutytruck, highway bus or other motor vehicle. In particular, thecombination radiator and charge air cooler heat exchanger packagedisclosed herein satisfies the requirements of these vehicles for lowcharge air pressure drops, to obtain maximum performance from theirturbo- and supercharges, while still providing satisfactory cooling tothe engine coolant and charge air. Additionally, these vehicles oftenoperate in high altitudes and low air density, which the heat exchangerpackage of the present invention is able to accommodate.

While the present invention has been particularly described, inconjunction with a specific preferred embodiment, it is evident thatmany alternatives, modifications and variations will be apparent tothose skilled in the art in light of the foregoing description. It istherefore contemplated that the appended claims will embrace any suchalternatives, modifications and variations as falling within the truescope and spirit of the present invention.

1-24. (canceled)
 25. A method for cooling fluids used in an engine of amotor vehicle, comprising: providing a heat exchanger assemblycomprising: a radiator for cooling engine coolant having opposite frontand rear faces through which cooling air flows, opposite upper and lowerends adjacent the faces, and sides adjacent the faces between the upperand lower ends; a charge air cooler for cooling charge air having upperand lower portions, each charge air cooler portion having opposite frontand rear faces through which cooling air flows, opposite upper and lowerends adjacent the faces, and sides adjacent the faces between the upperand lower ends, and including upper and lower manifolds extending acrossthe upper and lower ends, respectively, of each charge air coolerportion, and fluid-carrying tubes extending substantially directlybetween the upper and lower manifolds of each charge air cooler portion,the upper charge air cooler portion being disposed in overlappingrelationship and adjacent to the upper end of the radiator with theupper and lower ends of the upper charge air cooler portion beingoriented in the same direction as the upper and lower ends of theradiator, wherein the rear face at the upper end of the radiator isdisposed adjacent the front face of the upper charge air cooler portionand the upper manifold of the upper charge air cooler portion isdisposed adjacent the upper end of the radiator, cooled compressedcharge air exiting the charge air cooler through the upper manifold ofthe upper charge air cooler portion, the lower charge air cooler portionbeing disposed in overlapping relationship and adjacent to the lower endof the radiator with the upper and lower ends of the lower charge aircooler portion being oriented in the same direction as the upper andlower ends of the radiator, wherein the front face at the lower end ofthe radiator is disposed adjacent the rear face of the lower charge aircooler portion and the lower manifold of the lower charge air coolerportion is disposed adjacent the lower end of the radiator, the lowermanifold of the lower charge air cooler portion receiving incomingcompressed charge air to the charge air cooler, the lower end of theupper charge air cooler portion being in line with and opposite theupper end of the lower charge air cooler portion, the charge air coolerportions being operatively connected by a conduit extending from thelower manifold at the lower end of the upper charge air cooler portionand around a side of the radiator, intermediate the radiator ends, tothe upper manifold at the upper end of the lower charge air coolerportion such that the charge air may flow through the conduit betweenthe lower manifold of the upper charge air cooler portion and the uppermanifold of the lower charge air cooler portion; flowing the enginecoolant through the radiator from the upper end to the lower endthereof; flowing the charge air in sequence in through the lowermanifold of the lower charge air cooler portion, the tubes of the lowercharge air cooler portion, the upper manifold of the lower charge aircooler portion, the conduit extending from the upper manifold of thelower charge air cooler portion and around a side of the radiator,intermediate the radiator ends, to the lower manifold of the uppercharge air cooler portion, the lower manifold of the upper charge aircooler portion, the tubes of the upper charge air cooler portion, theupper manifold of the upper charge air cooler portion, and to an airintake manifold of the engine; and flowing cooling air through the heatexchanger assembly such that the cooling air flows sequentially firstthrough the lower end of the radiator and subsequently through the lowercharge air cooler portion, and the cooling air also flows sequentiallyfirst through the upper charge air cooler portion and subsequentlythrough the upper end of the radiator, to cool the engine coolant in theradiator and the charge air in the charge air cooler portions.
 26. Themethod of claim 25 wherein the dimension between the upper and lowerends of the charge air cooler portions is less than the dimension fromone side of the charge air cooler portions to the other side of thecharge air cooler portions, such that the fluid-carrying tubes extendacross the shorter dimension of the faces of the charge air coolerportions, and wherein, in each charge air cooler portion, the charge airflows between the upper manifold and the lower manifold through thetubes extending across the shorter dimension of the face thereof. 27.The method of claim 25 wherein the radiator includes fluid-carryingtubes extending in the same direction as the fluid-carrying tubes ofeach of the charge air cooler portions, and wherein the engine coolantflows through the radiator fluid-carrying tubes.
 28. The method of claim25 further providing at least one of the sides or ends of the radiatorextending outward of a side or end of one of the charge air coolerportions, and wherein the cooling air flows through theoutwardly-extending radiator side or end without flowing through thecharge air cooler portions.
 29. The method of claim 25 further providingthe upper end of the radiator extending outward of the upper end of theupper charge air cooler portion, and wherein the cooling air flowsthrough the outwardly-extending radiator upper end without flowingthrough the charge air cooler portions.
 30. The method of claim 25further providing the upper end of the radiator extending outward of theupper end of the upper charge air cooler portions and the lower end ofthe radiator extending outward of the lower end of the lower charge aircooler portion, and wherein the cooling air flows through theoutwardly-extending radiator upper and lower ends without flowingthrough the charge air cooler portions.
 31. The method of claim 25further providing at least one of the sides or ends of one of the chargeair cooler portions extending outward of a side or end of the radiator,and wherein the cooling air flows through the outwardly-extending chargeair cooler sides or ends without flowing through the radiator.
 32. Themethod of claim 25 wherein the charge air cooler portions areoperatively connected by conduits such that the charge air may flowbetween the upper manifold of the lower charge air cooler portion andthe lower manifold of the upper charge air cooler portion around bothsides of the radiator, intermediate the radiator ends.
 33. A heatexchanger assembly for cooling fluids used in an engine of a motorvehicle, comprising: a radiator for cooling engine coolant havingopposite front and rear faces through which cooling air flows, oppositeupper and lower ends adjacent the faces, and sides adjacent the facesbetween the upper and lower ends; a charge air cooler for cooling chargeair having upper and lower portions, each charge air cooler portionhaving opposite front and rear faces through which cooling air flows,opposite upper and lower ends adjacent the faces, and sides adjacent thefaces between the upper and lower ends, and including upper and lowermanifolds extending across the upper and lower ends, respectively, ofeach charge air cooler portion, and fluid-carrying tubes extendingsubstantially directly between the upper and lower manifolds of eachcharge air cooler portion, the upper charge air cooler portion beingdisposed in overlapping relationship and adjacent to the upper end ofthe radiator with the upper and lower ends of the upper charge aircooler portion being oriented in the same direction as the upper andlower ends of the radiator, wherein the rear face at the upper end ofthe radiator is disposed adjacent the front face of the upper charge aircooler portion and the upper manifold of the upper charge air coolerportion is disposed adjacent the upper end of the radiator, the lowercharge air cooler portion being disposed in overlapping relationship andadjacent to the lower end of the radiator with the upper and lower endsof the lower charge air cooler portion being oriented in the samedirection as the upper and lower ends of the radiator, wherein the frontface at the lower end of the radiator is disposed adjacent the rear faceof the lower charge air cooler portion and the lower manifold of thelower charge air cooler portion is disposed adjacent the lower end ofthe radiator, the lower end of the upper charge air cooler portion beingin line with and opposite the upper end of the lower charge air coolerportion, the charge air cooler portions being operatively connected by aconduit extending from the lower manifold at the lower end of the uppercharge air cooler portion and around a side of the radiator,intermediate the radiator ends, to the upper manifold at the upper endof the lower charge air cooler portion such that the charge air may flowthrough the conduit between the lower manifold of the upper charge aircooler portion and the upper manifold of the lower charge air coolerportion; and the heat exchanger assembly being oriented such that thecooling air flows sequentially first through the lower end of theradiator and subsequently through the lower charge air cooler portion,and the cooling air also flows sequentially first through the uppercharge air cooler portion and subsequently through the upper end of theradiator, to cool the engine coolant in the radiator and the charge airin the charge air cooler portions.
 34. The assembly of claim 33 whereinthe dimension between the upper and lower ends of the charge air coolerportions is less than the dimension from one side of the charge aircooler portions to the other side of the charge air cooler portions,such that the fluid-carrying tubes extend across the shorter dimensionof the faces of the charge air cooler portions, and wherein, in eachcharge air cooler portion, the charge air flows between the uppermanifold and the lower manifold through the tubes extending across theshorter dimension of the face thereof.
 35. The assembly of claim 33wherein the radiator includes fluid-carrying tubes extending in the samedirection as the fluid-carrying tubes of each of the charge air coolerportions, and wherein the engine coolant flows through the radiatorfluid-carrying tubes.
 36. The assembly of claim 33 wherein at least oneof the sides or ends of the radiator extends outward of a side or end ofone of the charge air cooler portions, and wherein the cooling air flowsthrough the outwardly-extending radiator side or end without flowingthrough the charge air cooler portions.
 37. The assembly of claim 33wherein the upper end of the radiator extends outward of the upper endof the upper charge air cooler portion, and wherein the cooling airflows through the outwardly-extending radiator upper end without flowingthrough the charge air cooler portions.
 38. The assembly of claim 33wherein the upper end of the radiator extends outward of the upper endof the upper charge air cooler portions and the lower end of theradiator extends outward of the lower end of the lower charge air coolerportion, and wherein the cooling air flows through theoutwardly-extending radiator upper and lower ends without flowingthrough the charge air cooler portions.
 39. The assembly of claim 33wherein at least one of the sides or ends of one of the charge aircooler portions extends outward of a side or end of the radiator, andwherein the cooling air flows through the outwardly-extending charge aircooler sides or ends without flowing through the radiator.
 40. Theassembly of claim 33 wherein the charge air cooler portions areoperatively connected by conduits such that the charge air may flowbetween the upper manifold of the lower charge air cooler portion andthe lower manifold of the upper charge air cooler portion around bothsides of the radiator, intermediate the radiator ends.